1. Field of the Invention
The invention relates to a cable reversing system for an automatic window lift.
2. Description of the Prior Art
The European patent document 385,167 A1 describes a cable reversing system for bowden-cable actuated window lifts of motor vehicles. In such a bowden-cable driven window lift, a cable transmits force directly from a drive to a mechanism acting on the window pane. This cable drive entails several different cable reversals inside the vehicle door. The cable reversal is implemented either by molded parts that force the cable over slide paths into the desired direction, or by cable pulleys allowing nearly frictionless cable reversal when compared to the case of the molded parts. The known cable reversing part is connected to a cross-sectionally contoured rail, herein "section rail", mounted inside the door box and can be hooked by a detent mechanism to the section rail, the shaft of the cable reversing system being integral with the cable reversing system. The reversing pulley can be mounted already before the pulley is mounted on a shaft and be secured using an expansion ring, though at the cost of some labor procedure.
In general significant cable forces are applied to the reversing pulleys of the bowden-cable window lifts and, depending on the configuration of the window-lift affixation points relative the bearings of the reversing pulleys, these forces may cause substantial leverage or bending torques.
The German patent document 36 15 578 C1 discloses apparatus to raise and lower a vehicle window pane and comprising four stationary reversing pulleys enclosed by a closed bowden cable passing through a displacement actuator and connecting to holding means affixed to the window pane. This known apparatus is mounted on a guide frame supporting all apparatus components and is fitted with guide posts connected by crossbeams and with guide channels to guide the holding means connected to the bowden cable. This design incurs the drawback that its guide frame is bulky, especially because of the distances, some significant, between its affixation points and the bearings of the reversing pulleys, in order to withstand cable forces or to allow for premature wear. As a result this known apparatus is comparatively heavy.
To date, it has been conventional practice to place the affixation points of a bowden-cable window lift in the guide rails or at retaining angles or base plates mounted to these rails, the retaining angles sometimes being fitted with reversing pulleys and in such designs being affixed to the ends of the guide rails (German patent document 36 38 059 C2).
It is further known to fit a borehole into the cable reversing part and the section rail and to rivet in place the cable reversing pulley (German patent document 41 31 098 C2). During its assembly to the vehicle, the reversing pulley is screwed into the vehicle sheetmetal. This design entails a comparatively large number of parts to mount the cable pulley or the cable reversing part.
The European patent document 0,744,522 A1 discloses a cable reversing part, used for window lifts, which can be hooked into a support beam, the reversing pulley being seated on a comparatively large plastic shank. This pulley is held in place on one side by the plastic of the cable reversing part and on the other side by the metal of the support beam. There is the possibility at high tensions in the cable that the mutually displaceable shank parts supporting the reversing pulley shall warp, entailing higher friction and perhaps wear.